Royal Ascent
By: Due to their high resistance to rattlesnake venom, king snakes can take on rattlesnakes with the utmost confidence. This key adaptation allows kings to successfully hunt and consume snakes that might otherwise seem too large or dangerous. The kingsnake typically achieves victory by overpowering the rattlesnake through very effective constriction. Therefore, even a stout rattlesnake (like the big boy in the video) can be defeated if the kingsnake manages to gain control first.
However, their immunity to venom is not universal. Scientific evidence shows that the potent neurotoxic venom of coral snakes (Micrurus or Micruroides genera) can still be lethal to a king snake. Although they do hunt and eat coral snakes, and can tolerate small bites, the coral snake's high toxicity and mechanism challenge the kingsnake's defenses more severely than pit viper venoms.
Note: Snake venom is built to harm through injection, not digestion, so eating a venomous snake is usually not dangerous from the venom itself unless the kingsnake has damaged tissue in the mouth or digestive tract that could allow the venom enter the bloodstream.